ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

4pPA11. Numerical study of the effective impedance of an idealized
thermoacoustic stack.

A. S. Worlikar

Dept. of Mech. Eng., Johns Hopkins Univ., Baltimore, MD 21218

R. Klein

Institut fur Technische Mechanik, 52056 Aachen, Germany

O. M. Knio

Johns Hopkins Univ., Baltimore, MD 21218

A low-Mach-number, compressible flow, simulation model is used to compute
unsteady oscillatory flow in the neighborhood of a thermoacoustic stack. The
model relies on a vorticity-based formulation of the mass, momentum, and energy
conservation equations. The numerical scheme incorporates a highly efficient
construction which combines a domain decomposition boundary Green's function
formulation with fast Fourier inversion methods. Computed results are used to
calculate the effective impedance of the device, which accounts for
contributions of both linearized acoustic phenomena and nonlinear inertial
effects. The dependence of this effective impedance on stack configuration and
on acoustic driving amplitudes and frequencies is also analyzed. [Work supported
by the Office of Naval Research.]